JP2000160989A - Cutter bit for shield machine and shield machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the mechanical load of excavating edges and an outer ring by fitting a plurality of cutter bits to the front face of a spoke protrusively forwardly than the excavating edges and outwardly than the outer ring. SOLUTION: Many excavating edges 6 are fixed on both sides of the spoke 3 of the cutter disk of a shield machine, and they are rotated for an excavation. A plurality of cutter bits 10 are fitted to the front face of the spoke 3 protrusively forwardly than the excavating edges 6 by the size B, and the cutter bits 10 on the outermost periphery are protruded outwardly than the outer ring 5 by the size A. Circular holes are formed on a base material 11 made of carbon steel for a mechanical structure, cylindrical cemented carbide tips made of a cemented carbide alloy are inserted, buried, brazed, fixed, and planted in zigzag in three lines and seven rows with semispherical tip sections exposed to form the cutter bit 10. Mechanical loads applied to the outer ring 5 and the excavating edges 6 are sharply reduced, and excavation performance can be stably maintained over a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cutter bit used for protecting a cutter disk and a cutting blade in a shield machine (particularly for excavating a gravel layer), and an arrangement of the cutter bit. It relates to a shielded excavator.

[0002]

2. Description of the Related Art A shield excavator has a rotary cutter disk at the forefront and a plurality of excavating blades (a scraper for shaving the ground) on the front surface thereof (a front view of the shield excavator 1). Reference numeral 2 denotes a cutter disk, and reference numeral 6 denotes a digging blade. However, the drawing omits a part of the digging blade 6 and the like). By rotating the cutter disk, the earth is excavated by the action of the excavation blade.

However, when excavating a so-called gravel layer containing a lot of sand or cobblestone, unlike when excavating a clay layer or the like, the excavating blade is easily worn or broken, and the cutter disk itself is severely worn. There is. In particular, the outermost peripheral portion of the cutter disk has a high peripheral speed due to the rotation and constantly comes into contact with the excavated soil at the lower portion, so that the abrasion proceeds rapidly on both the excavating blade and the cutter disk. Wear or breakage of the cutting edge at the outermost periphery directly leads to the disadvantage that the outer diameter of the tunnel to be cut becomes small or the damage to the cutter disk is accelerated. Further, when the outer peripheral ring of the cutter disk (the portion denoted by reference numeral 5 in FIG. 3) is broken due to wear, the connection between the spokes (reference numeral 3 in FIG. 3) constituting the cutter disk is broken, and the rigidity of the cutter disk is significantly reduced. I do.

[0004] For this reason, a cutter bit different from a normal digging blade may be used together with the cutter disk in order to protect the outermost portion (the digging blade and the outer ring). FIGS. 4 to 6 show such a conventional protection cutter bit, which is arranged at the outermost peripheral portion of a cutter disk or the like to reduce the load on the excavating blade and the outer peripheral ring. First, a cutter bit 20 shown in FIG. 4 has a base material 21 made of tool steel or the like and a cemented carbide tip (carbide tip) 22 made of tungsten carbide (WC) or the like brazed to both ends of the base material 21. Then, as shown in the figure, the tip 22 is attached to the front and rear surfaces in the rotation direction (left and right in the figure) of the cutter disk 2,
The tip of the tip 22 faces forward (upward in the figure) in the excavation direction of the excavator. The cutter bit 30 shown in FIG. 5 is similarly obtained by embedding and brazing a cemented carbide tip 32 in a base material 31, and at the front and rear positions in the rotation direction.
With its tip facing forward in the digging direction. The cutter bit 40 shown in FIGS. 6A and 6B has a small flat carbide tip 42 in a fan-shaped plate-like base material 41.
Are buried, and the longitudinal direction of the base material 41 is oriented in the circumferential direction (rotation direction) of the cutter disk 2 as shown in FIG. 3A, and the tip of the chip 42 is directed forward in the excavation direction as shown in the figure. It is arranged on the outermost periphery of the cutter disk 2. A cutter bit similar to that shown in FIG. 3 is described in Japanese Patent Publication No. 57-33439.

[0005]

However, the cutter bit for protection shown in FIGS. 4 to 6 does not necessarily have sufficient strength per se, and depending on the formation or the like, the function of the cutter bit may be shortened in a short time. May be lost. For example, in the cutter bit 20 shown in FIG. 4, since the cemented carbide tip 22 is only fixed to the base material 21 on one side only, the tip 22 falls off the base material 21 due to an impact or the like when hitting gravels. There is a possibility that. In the cutter bit 30 shown in FIG. 5, the base material 31 around the cemented carbide tip 32 is liable to wear as shown by the imaginary line in the figure.
Is likely to fall off. Further, if the cutter bit 40 in FIG. 6 contacts the ground only in the rotation direction (left and right in the figure) of the cutter disk 2, even if a part of the cutter bit wears as shown by the phantom line, the further wear occurs. Although it can be said that it does not easily progress and hardly breaks, in reality, excavated earth and sand and the like come into contact with the cutter bit 40 while moving in an irregular direction. Can fall off, and the possibility that the base material 41 and the like can be damaged by an out-of-plane impact force cannot be denied. If the service life of the protective cutter bit is so short,
Drilling blades and outer rings cannot be effectively protected.

[0006] The claimed invention has a cutter bit which is excellent in wear resistance and impact resistance and has no directional restriction, and can protect a drilling blade and a cutter disk for a long period of time; It is intended to provide a shield machine equipped with such a machine.

[0007]

According to a first aspect of the present invention, there is provided a cutter bit for a shield machine, comprising: a plurality of cylindrical carbide tips having a tip protruding above a surface of a base material and having a full circumference at other portions; Are embedded in the base material in the state of being enclosed. As the base material, tool steel, carbon steel for machine structural use, structural alloy steel, and other hard steels are desirable.For the material of the cemented carbide tip, in addition to cemented carbide such as tungsten carbide, cermet, ceramics, diamond A sintered body, a cBN sintered body, or the like can be employed. The embedded carbide tip is integrated with the base material so as not to come off by brazing all around, or by tightly fitting into a hole in the base material and screwing the base.

[0008] Such a cutter bit is mounted on the outermost peripheral portion of a rotary cutter disk of a shield machine, and when rotated together with the disk, the ground of the corresponding portion is caused by the action of a carbide tip having a protruding tip. The mountain can be dislodged to reduce the mechanical load (load on excavation) of the outer ring of the cutter disk and the excavation blade. Although the base material is more susceptible to wear than a carbide tip, when the surface of the base material is worn, the amount of protrusion of the chip from the surface increases accordingly, so that the above-mentioned original function is not suddenly lost. In addition, when the amount of protrusion of the chip increases, the chance of contact between the base material and the earth and sand or the like decreases, so that the wear of the base material hardly progresses further.

This cutter bit is supported only from one side or two sides because the entire periphery of the part other than the tip part of the carbide tip is surrounded by the base material and receives a supporting force therefrom. Unlike the examples of FIGS. 4 to 6, the support is strong without making the directionality a problem, so that the impact resistance and wear resistance are much higher. The excellent impact resistance is because the chip is not easily dropped even if an impact force is applied because the chip is supported all around by the base material, and the high abrasion resistance is This is because even if the base material is worn on one side near the tip, the supported tip does not fall off from the entire circumference. Further, since the chip is supported around the entire periphery, the chip exhibits the above-described excellent wear resistance and impact resistance even when a force is applied from any direction due to ground, earth and sand.

The fact that the cemented carbide tip can be embedded in the base material all around, unlike the conventional one, is related to the fact that the cemented carbide tip is formed in a columnar shape as described above. FIG. 4-
In the example of FIG. 6, since the chip is rectangular, it is difficult to form a hole in the base material that tightly surrounds the chip all around the chip by machining (since sufficient strength is required, The base material including the hole cannot be formed by casting). However, since the tip of the cutter bit of the invention has a cylindrical shape, a hole into which the tip is fitted can be easily formed by a drill or the like. In other words, in this cutter bit, since the cemented carbide tip is cylindrical, it is easy to form a hole for embedding the tip in the entire circumference in the base material, and therefore, has a high wear resistance. It can be said that it has become possible to support the chip so as to provide the chip with impact resistance.

A cutter bit according to a second aspect is characterized in that the arrangement of the embedded carbide tips on the surface of the base material is staggered. The staggered arrangement refers to an arrangement with respect to a grid arrangement, which is used as an arrangement of tube groups in a heat exchanger. From staggered arrangement,
As a matter of course, chips may be provided over a plurality of rows and a plurality of columns.

With such a cutter bit, the above-mentioned wear resistance and impact resistance are particularly excellent, and the above-mentioned functions are stably exhibited for a long period of time. The first reason is that, in the case of the staggered arrangement, the distance between the adjacent carbide tips can be larger than in the case of the grid arrangement, even if the size of the base material is the same. The fact that the distance between adjacent chips can be increased means that the base material surrounding the chips can be made thicker by that amount, so that the chip support becomes stronger and the impact resistance is improved, and the base material is improved. It takes a long time for the wear of the material to reach the adjacent tip position. The second reason is that the carbide tips are arranged in a plurality of rows and a plurality of columns. Although the wear of the base material usually occurs on one side, even if the wear of the base material from one side progresses and some carbide tips on that side fall off, they may be placed in rows or columns far from the side. The cutter bit does not lose its function for a long period of time because some inserts are still firmly supported by the base material.

[0013] The cutter bit according to a third aspect of the present invention is further characterized in that a hardened build-up welding layer is formed on a side surface of the base material (side surface adjacent to a surface from which the tip of the carbide tip protrudes). .

Since the hardfacing weld layer is formed in this way, the wear of the base material from the side surface is effectively suppressed with this cutter bit. Abrasion from the surface of the base material from which the carbide tips protrude, as described above, progresses to a certain extent and the progress of the tips becomes slower at the stage where the amount of protrusion of the tips increases, so if the wear from the side surfaces is suppressed in this way. The base material of the cutter bit does not wear hard from any direction. Since the wear hardly progresses, the periphery of the cemented carbide tip is surrounded by a thick base material for a long period of time, and therefore, it can be said that this cutter bit exhibits extremely high wear resistance and impact resistance.

According to a fourth aspect of the present invention, the cutter bit is attached to the outermost peripheral portion of the rotary cutter disk, and the outer end of the cutter bit is positioned on the outer peripheral surface of the outer peripheral ring of the cutter disk. It is characterized in that it is provided at a position outside the outermost end of the outermost excavation blade (original excavation blade that scrapes the ground as a scraper) at the same level or more than the outermost end. Here, “outside” refers to the outside in the radial direction of the cutter disk (the same applies hereinafter).

In this shield machine, the cutter bit is attached to the outermost peripheral portion of the rotary cutter disk, and the outer end of the bit is provided outward as described above. However, due to the action of the carbide tip, the ground of the corresponding portion is dislodged, and the mechanical load on the outer peripheral ring of the cutting blade or the cutter disk at the outermost peripheral position is reduced. Therefore, in this shield machine, wear of the outermost excavation blade and the outer ring with the highest load is prevented, and the impact of the gravel (cobble) on the cutting edge is prevented, so that the cutter disk and the excavation are prevented. The smooth excavation function by the blade is stably exhibited for a long time. Although a large load acts on the cutter bit instead, the cutter bit has a long service life based on the above-described impact resistance and wear resistance, and effectively protects the excavating blade, the outer peripheral ring, and the like for a long period of time.

In a shield machine according to a fifth aspect of the present invention, a plurality of cutter bits having the above-described structure are mounted on the front surface of the rotary cutter disk (the front surface in the direction of excavation of the machine). Front end in the direction of excavation)
Is provided at a position in front of the front end of the excavation blade (in front of the excavator in the excavation direction).

A large number of cutting blades are arranged on the front surface of the rotary cutter disk as described above (see FIG. 3).
These ordinary digging blades function as scrapers to scrape the ground and generally have sharp ridges at the tip, so they may be damaged by large gravel or lose their function in a short time due to wear. There are many. However, if such a cutter bit is arranged at a position ahead of the front end of such a cutting blade, the cutter bit breaks or loosens the ground before the cutting blade digs the ground. Will be. Therefore, the mechanical load acting on the digging blade is reduced, and therefore, the digging blade is prevented from being damaged or rapidly worn. The cutter bit has a large load acting on it, but the bit has excellent impact resistance and abrasion resistance as described above, and has a long service life. Excavation function is maintained long and smooth.

[0019]

1 to 3 show an embodiment of the present invention. 1A and 1B show the vicinity of the outermost periphery of the shield machine 1. FIG. 1A is a front view (detailed view of a portion I in FIG. 3), and FIG. 1B is bb in FIG. It is sectional drawing. FIG. 2 is a detailed view of the cutter bit 10 used in the excavator 1 of FIG. 1, wherein FIG. 2 (a) is a plan view, FIG. 2 (b) is a side view, and FIG. 2 (c) is c in FIG. FIG. 3D is a cross-sectional view, and FIG. 4D is a view taken along the line dd in FIG. FIG. 3 is a front view showing the rotary cutter disk 2 as viewed from the front of the shield machine 1.

As shown in FIG. 3, the shield machine 1
A cutter disk 2 which is rotationally driven by driving means (not shown) such as a motor is provided at the forefront. The cutter disk 2 includes a plurality of spokes 3 radially extending from a central portion, a plurality of intake ports 4 for sediment formed between the spokes 3, and an outer peripheral ring 5 connecting the foremost portions of the spokes 3. It is constituted by such as. A large number of excavating blades 6 are attached to both sides (both sides in the circumferential direction) of each spoke 3 so as to face the intake port 4 and protrude from the front surface of the cutter disk 2. Since the rotation direction of the cutter disk 2 is sometimes switched, these excavating blades 6 are symmetrically arranged on both sides of the center of the spoke 3 so that the directions are different by 180 °. FIG.
As shown in (b), these excavating blades 6 are obtained by fixing a carbide tip 8 to the tip of a base material 7 made of tool steel, and function as a scraper by using a sharp edge of the tip 8, and The ground is excavated by rotating together with the cutter disk 2 while being pressed against the ground (face). The earth and sand generated by the excavation enters into a chamber (not shown) behind the cutter disk 2 through the intake port 4, and is discharged backward by a discharging means such as a conveyor.

The above-described excavating blade 6 excavates various stratum portions except for the bedrock satisfactorily. However, when excavating a gravel layer, the excavating blade 6 may receive considerably severe wear and impact. This is because when excavating the gravel layer, small gravel flows vertically and horizontally on the surface of the excavation blade 6, and large gravel exerts a strong impact force on the excavation blade 6. In particular, the excavating blade 6 arranged on the outermost periphery of the cutter disk 2 is particularly susceptible to wear and breakage because it has a high moving speed due to rotation (therefore, the excavating distance is long) and comes into contact with earth and sand without interruption. The outer ring 5 of the cutter disk 2 also receives a strong load when excavating a gravel layer, for the same reason, and the wear tends to progress faster.

In this shield machine 1, in consideration of this point, as shown in FIG. 3, on the front surface of the spoke 3 including the outermost periphery of the cutter disk 2, the load on the outer peripheral ring 5 and the excavating blade 6 is reduced. A plurality of cutter bits 10 are attached. In the cutter bit 10 provided on the outermost peripheral portion of the cutter disk 2, the outer end (closer to the outer periphery of the cutter disk 2) has a dimension A (approximately smaller than the outer peripheral surface of the outer peripheral ring 5) as shown in FIG. 20mm) outwardly,
Accordingly, the excavation blade 6 is arranged so that its end is located outside the tip of the outermost excavation blade 6 or more. Further, with respect to all the cutter bits 10 including the outermost one, the front end (the front end in the excavation direction of the excavator 1) has a front end which is larger than the front end of the excavation blade 6 at the same radial position. Dimension B
(Approximately 20 mm). By protruding the end of each cutter bit 10 outward and forward in this manner, the load applied to each excavating blade 6 and the outer peripheral ring 5 by the ground and earth and sand is reduced, and their wear and breakage are less likely to occur. It is.

Each cutter bit 10 is, as shown in FIG.
It is composed of a base material (substrate) 11 made of carbon steel for machine structure (S45C) and a cemented carbide tip 12 made of cemented carbide (PR50). First, the base material 11 has front and rear end portions (FIG. 2A) while forming the general shape into a substantially rectangular parallelepiped.
(Left and right in the figure) are sharp and narrow.
As shown in FIG.
The front and rear end portions are sharpened so that the ground can be easily cut in consideration of the fact that they are arranged along the rotation direction. Then, as shown in FIGS. 2A and 2C, a plurality of holes 11c having a circular cross section are formed in the upper surface (front surface) 11a of the base material 11 by machining, and the plurality of holes 11c in the columnar carbide tip 12 are formed there. The base 12b is inserted and fixed. The arrangement of the holes 11c and the chips 12 was a staggered arrangement of 3 rows and 7 columns as shown in FIG. 2A, so that the base material 11 remained as thick as possible between adjacent chips 12. The chip 12 is fixed by brazing. A silver braze is poured into the hole 11c of the base material 11, the base 12b of the chip 12 is inserted, and the entire periphery is fixed to the base material 11 by brazing. Tip 1 of each chip 12
2a is projected on the upper surface 11a of the base material 11 with the chip 12 inserted and fixed in the base material 11 in this way. The tip portion 12a may be sharpened, but in that case, it is formed in a hemispherical shape because it wears out early. Further, the hard metal layer 13 is formed on the outer wall portion of the side surface 11b surrounding the portion in which the chip 12 is embedded in the base material 11, as shown in the drawing. The purpose of the metal layer 13 is to suppress the progress of wear of the base material 11 around the base 12b of the chip 12 as much as possible so that the chip 12 does not easily fall off.

When the cutter bit 10 is attached to the cutter disk 2 and rotates together with the disk 2 as described above, the tip of the carbide tip 12 protrudes to break or loosen the ground due to the action of the tip 12a. Demonstrate function. The cutter bit 10 does not have an edge portion that is easily damaged by an impact force received from a specific direction, and does not include a portion where wear is particularly likely to progress. In addition, as for each chip 12, the base 12b is supported by the base material 11 over the entire circumference, and a plurality of chips 12 are provided on the base material 11 in a staggered arrangement. However, the above functions are not completely lost. Therefore, the above function of the cutter bit 10 breaking or loosening the ground is maintained for a long time.

By providing the cutter bit 10 outside and in front of the cutter disk 2 as described above, the mechanical load acting on the outer peripheral ring 5 and all the cutting blades 6 is greatly reduced. When the load is reduced on both the outer peripheral ring 5 which plays an important role of supporting the mechanical strength of the spokes 3 of the cutter disk 2 and the digging blade 6 which is easily damaged by wear and impact, the gravel layer is reduced. Even when excavating, the excavating performance of the shield excavator 1 is stably maintained for a long time. Needless to say, the function of the cutter bit 10 that receives a mechanical load in place of the excavating blade 6 and the like is less likely to lose its function due to abrasion and impact as described above.

[0026]

The cutter bit for a shield machine described in claim 1 has the following effects. 1) In order to exhibit excellent abrasion resistance and impact resistance even when a load is applied from any direction due to ground, earth and sand, etc., when mounted on the rotary cutter disc of the shield machine, Functions such as breaking can be exhibited over a long period of time.

2) When attached to the outermost peripheral portion or the front surface of the rotary cutter disk of the shield machine,
The mechanical load on the outer ring of the cutter disk and the cutting edge is reduced, which contributes to the long-term stable performance of the shield machine.

3) Since the cemented carbide tips are columnar, the support of the cemented carbide tips by the base material can be strengthened and the manufacture is easy. It is easy to manufacture because it is easy to form a columnar hole for embedding the chip in the base material.

In the cutter bit according to the second aspect of the present invention, 4) the arrangement of the cemented carbide chips on the base material is staggered, so that all the chips do not fall off from the base material at the same time, and Support is particularly strong. Therefore,
As a cutter bit, it excels in wear resistance and impact resistance, and exhibits the function of 1) above for a longer period of time.

[0030] The cutter bit according to claim 3 further has: 5) a hardened build-up welded layer on the side surface of the base material, so that abrasion of the base material from the side surface is effectively suppressed, and the wear resistance of the cutter bit is improved. And impact resistance are even higher.

In the shield machine according to the fourth aspect of the present invention, 6) since the cutter bit is attached to the outermost periphery of the cutter disk so as to protrude outward, the outermost excavation blade with a high load, The outer peripheral ring, which is particularly important for the strength of the cutter disk, is effectively protected from abrasion and impact due to contact with gravel and the like.

7) The above-mentioned cutter bit is excellent in wear resistance and impact resistance despite its high load and has a long life, so that the excavating function of the shield excavator is stably exhibited for a long period of time. You.

The shield machine according to claim 5 further comprises: 8) the cutter bit is arranged at a position forward of the front end of the cutting blade on the front surface of the rotary cutter disk, so that the machine for the cutting blade is machined. Load is reduced, and the excavating function of the shield machine is smoothly maintained for a longer period of time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a part of a shield machine 1 to introduce an embodiment of the present invention. FIG. 1A is an enlarged front view of a part of the cutter disk 2 (the part I in FIG. 3), and FIG.
It is sectional drawing.

FIG. 2 is a detailed view of a cutter bit 10 attached to the shield machine 1 of FIGS. 1 and 3; FIG. 2A is a plan view (a view from the front of the cutter disk 2).
(B) is a side view, and (c) is cc in (b).
FIG. 3D is a cross-sectional view, and FIG.

FIG. 3 is a front view of the rotary cutter disc 2 as viewed from the front of the shield machine 1; However, some of the excavating blades 6 and the like are omitted.

FIG. 4 is a side view showing a conventional cutter bit 20.

FIG. 5 is a side view showing another conventional cutter bit 30.

FIG. 6 is a front view (FIG. 6A) and a side view (FIG. 6B) showing another conventional cutter bit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shield machine 2 Rotary cutter disk 5 Outer ring 6 Drilling blade 10 Cutter bit 11 Base material 12 Carbide tip 13 Hard metal layer (hardened overlay)

Claims (5)

[Claims] A plurality of columnar carbide tips are embedded in the base material with their tips protruding above the surface of the base material and surrounding the entire periphery at other portions. And cutter bits for shield machine. 2. The cutter bit for a shield machine according to claim 1, wherein the arrangement of the embedded carbide tips on the surface of the base material is a staggered arrangement. 3. The cutter bit for a shield machine according to claim 1, wherein a hardfacing weld layer is provided on a side surface of the base material. 4. A cutter bit according to claim 1, wherein the cutter bit is attached to an outermost peripheral portion of a rotary cutter disc, and an outer end of the cutter bit is formed on an outer peripheral surface of an outer peripheral ring of the cutter disc. A shield excavator, wherein the shield excavator is located at a position outside of the position and at least as far as the outside end of the outermost cutting edge. 5. The rotary cutter disk according to claim 1, wherein a plurality of cutter bits are attached to a front surface of the rotary cutter disk, and a front end thereof is located at a position forward of a front end of the cutting blade. The shield machine according to claim 4, characterized in that: